Grid welding machine

ABSTRACT

A welding machine for manufacturing wire nets from mutually perpendicular longitudinal and transverse wires welded at the points of intersection comprises a device for feeding the longitudinal wires in a horizontal welding plane, two devices for simultaneously inserting two transverse wires (Q,Q&#39;), arranged at equal distances on either side of insertion lines (K,K&#39;), a welding electrode arrangement for carrying out two-point welding in the direction of the longitudinal wires, and two feeder arms (8,9) for transferring the transverse wires from the insertion lines to the welding lines (S, S&#39;). The feeder arms are fitted with clamping devices (11,12) for the transverse wires and can be moved together back and forth between the insertion lines and the welding lines along predetermined tracks (U, U&#39;; O, O&#39;). At least one of the feeder arms can be moved by means of a mechanical drive (22) in order to prestress both transverse wires relative to the other feeder arm in the direction of the transverse wires, and the transverse wires are positioned precisely in accordance with the predetermined distribution of the transverse wires by means of pivotable positioning elements (17,17&#39; ) provided in the region of the welding lines.

FIELD OF THE INVENTION

The invention relates to a welding machine for manufacturing grids fromlongitudinal and transverse wires intersecting one another at rightangles and welded at the intersections, having a device for deliveringthe longitudinal wires in a horizontal welding plane, two mutuallyspaced apart devices, disposed on feed lines, for simultaneous feedingor injection of two transverse wires, a welding electrode arrangementfor performing double spot welding in the direction of the longitudinalwires, and two feeder arms for transferring the transverse wires fromthe feed lines to the welding lines; the feeder arms are disposedoutside the outer longitudinal wires and are movable back and forth onpredetermined paths of motion between the feed lines and the weldinglines, by means of a common feeder arm holder extending at right anglesto the longitudinal wire direction.

In a grid welding machine known from Austrian Patent 267.293, twotransverse wires are simultaneously delivered to two feed lines disposedat a fixed distance from one another, pushed forward to the weldinglines by means of transverse wire feeders, and there welded to thelongitudinal wires with the aid of double spot welding electrodes. Onedisadvantage of this known grid welding machine is that only gridshaving a single predetermined, invariable transverse wire spacing, whichis equivalent to the mutual spacing of the transverse wire feed lines,can be produced.

In a grid welding machine of the type described initially above andknown from Austrian Patent 373.799, this disadvantage is overcome; herethe positionally fixed feed lines of the two transverse wires aredisposed at a fixed mutual spacing, while contrarily the two weldinglines are of variable position. The transfer of the transverse wiresfrom the feed lines to the welding lines is effected with a separatefeeder for each transverse wire, and the feeders are mounted on a commonholder. The transverse wire feeders can be disposed both between thelongitudinal wires, in other words within welding range, and outsidewelding range. In this known machine, however, triggering the transversewire feeders entails considerable expense and is often superfluous,because in most applications standard grids with transverse wirespacings that amount to a multiple of a predetermined minimum basicspacing are produced. Both of the above-described known grid weldingmachines also have the disadvantage that the transverse wires rest withvariably good alignment loosely in recesses of the transverse wirefeeder apparatuses. Especially with close-meshed grids with a smalltransverse wire spacing and small transverse and longitudinal wirediameters, this results in an asymmetrically structured finished gridweb.

Although it is known from Soviet Union Patent 837.668 to clamp atransverse wire during its delivery to the welding line, neverthelessthe clamping force is not adjustable but instead depends on thestructurally dictated increase in spacing between the clamping jawsduring the delivery movement and on the spring constants of any reliefsprings that may be provided.

THE INVENTION

The object of the invention is to create a grid welding machine of thegeneric type described at the outset above that makes it possible, whileexploiting the advantages of double spot welding, to produce grids thetransverse wire spacing of which is equivalent to a predeterminedminimum basic spacing or a multiple of this basic spacing of thetransverse wires, in a structurally simple and operationally reliableway. Briefly, the welding machine according to the invention isdistinguished by the fact that the feeder arms are embodied forreceiving both transverse wires jointly and are equipped with clampingdevices for the transverse wires; that at least one of the feeder arms,for joint prestressing of both transverse wires, is movable relative tothe other feeder arm in the transverse wire direction by means of amechanical drive mechanism with adjustable clamping force; and thatpositioning devices pivotable in the range of the welding lines areprovided for exact positioning of the transverse wires in accordancewith the predetermined transverse wire spacing.

Because both transverse wires are clamped simultaneously prior to beingwelded to the longitudinal wires, with a clamping force that can beadjusted to the transverse wire material, the irregularities in thetransverse wires dictated by the alignment processes are advantageouslycompensated for, and production-dictated asymmetries in the finishedgrid, which for instance also occur from thermal expansions during thewelding, are avoided. The positioning devices assure that the exacttransverse wire spacing is adhered to, and also effect a damping of thevibrations arising in the transverse wires as they are transferred.According to the invention, grids with transverse wire spacings that areeach a multiple of a predetermined minimum basic spacing, and inparticular close-meshed grids, can be manufactured with high accuracy.

It should be noted that from Examined German Applications 1.552.137 and1.566.526, for welding machines of a different kind, it is known toembody the feeder arms for receiving both transverse wires jointly.

In a preferred embodiment of the invention, at least one of the feederarms is disposed on the feeder arm holder such that it is displaceablerelative to the other feeder arm, for positioning. This makes itpossible to adjust the machine to different grid widths. Preferably, thepaths of motion of the feeder arms for the transverse wires from thefeed lines to the welding lines, and the paths of motion for the returnmovement are each composed of one forward feed segment and one rockingmotion segment.

In another characteristic of the invention, the welding machine isdistinguished by the fact that the clamping devices for the transversewires have lower clamping jaws that are openable and closable andcooperate with associated upper clamping jaws; the upper clamping jawsare each provided with a plurality of detent recesses for receiving thetransverse wires, and the mutual spacing between these recesses isequivalent to the predetermined minimum transverse wire spacing. In thisway, the transverse wires are held perfectly firm for the clampingprocess and for transfer. Grids can also be produced in which thespacing of the transverse wires amounts to a multiple of a minimumpossible basic spacing of the transverse wires.

A further feature of the invention has the characteristics that theupper clamping jaw of the clamping device on the feed side forms acutting tool, and that at least two transverse wire feeds are providedin a nozzle block on the feed side, the outlet side of which block has acutting edge for cooperation with the upper clamping jaw, forming thecutting tool, of the clamping device toward the feed, in order to severthe transverse wires from the wire stock.

According to the invention, the feeder arm remote from the delivery sideis preferably pivotable in the transverse wire direction by themechanical drive mechanism, which preferably has a clamping lever thatis actuatable by means of a hydraulic cylinder that can be acted upon byadjustable pressure.

DRAWINGS

Further characteristics of the invention are described in detail belowin an exemplary embodiment of the invention, referred to the drawings.Shown are:

FIG. 1, a perspective, schematic view of the essential elements of awelding machine according to the invention;

FIG. 2a, schematically, the pickup and transfer positions and the pathsof motion of the clamping devices for the transverse wires, seen in thedirection of the arrows IIa--IIa of FIG. 2b;

FIG. 2b, a detail section taken through the clamping devices along theline IIb--IIb of FIG. 2a; and

FIGS. 3a and 3b, the dispositions of the welding electrodes and possiblewelding positions of the transverse wires in the welding machineaccording to the invention.

DETAILED DESCRIPTION

In the grid welding machine shown in FIG. 1, two transverse wires Q, Q'are welded simultaneously in two welding lines S, S' with longitudinalwires L pushed toward them in the production direction P₁ to make a gridweb. The finished grid web is pulled out of the welding lines by meansof feed rollers, not shown. The longitudinal wires L are delivered tothe welding lines S, S' via a plurality of guide blocks 1 disposed sideby side, only one of which is shown in FIG. 1. Each guide block 1 hassubstantially a plurality of introduction nozzles side by side, whichsuitably comprise wear-resistant material and are equipped withlongitudinal wires L in accordance with the desired longitudinal wirespacing. For each introduction nozzle, each guide block 1 also has alower and upper guide prism, preferably V-shaped, following the guidenozzle; the guide prisms are each pressed against the longitudinal wiresby means of a spring steel sheet, to assure exact guidance of thelongitudinal wires L. The guide blocks 1 are disposed on a rail (notshown) such that they are adjustable transversely to the productiondirection P₁.

From supply coils, not shown, and by means of feed and alignmentdevices, two transverse wires Q, Q' at a time are simultaneouslyintroduced, via a nozzle block 2 provided with a plurality of feednozzles, into two feed or insertion lines K, K' in the direction of thearrow P₂ at right angles to the production direction P₁ at a selectablemutual spacing corresponding to the desired transverse wire spacing inthe finished grid. Each feed line K and K' is defined by recesses, whichare formed between a plurality of rigid plates 3, 3' locatedtransversely to the group of longitudinal wires and a plurality ofpivotable flaps 4, 4' located exactly opposite the plates. The recessesare merely roughly adapted to the transverse wire diameter; only therecess R located farthest away from the nozzle block 2 is provided witha centering piece adapted accurately to the transverse wire diameter,for the sake of accurate fixation of the transverse wires Q, Q'. Withtheir upper end, the plates 3, 3' are secured to a plate holder 5, 5'extending across the width of the machine. The flaps 4, 4' are supportedby their upper end each against a flap shaft 6 and 6', respectively,which also extend across the width of the machine and are pivotable asindicated by the double arrow P₃. The pivoting motion of the flap shafts6, 6' is effected by means of a swivel apparatus 7 formed by a cam plateand rocking levers. As a result, the feed lines K, K' are freed for thetransfer, to be described below, of the transverse wires Q, Q' into thewelding lines S, S'.

The feed nozzles in the nozzle block 2 have a mutual spacing equivalentto the minimum possible basic spacing a of the transverse wires in thegrid to be produced, and are also adapted in their dimensions to thediameter of the transverse wire to be processed. The amount of theminimum possible basic spacing a depends above all on the type of gridto be produced, for instance whether its spacing is based on inches oris metric.

The transfer of the transverse wires Q, Q' from the feed lines K, K'into the welding lines S, S' is effected by means of two pivotablefeeder arms 8, 9, each of which is disposed on the machine frame on theouter side edge of the grid web to be produced. The two feeder arms 8, 9are secured to a common holder 10. The feeder arm 9 remote from the feedside is displaceable on the holder 10 t right angles to the productiondirection P₁ as indicated by the double arrow P₄, so that it can assumeany intermediate position Z indicated by dashed lines that makes itpossible to produce grid webs with a selectable width, in other wordswith a selectable transverse wire length.

The feeder arm 8 on the feed side is provided with a clamping device 11,which in the pickup position defined by the feed lines K, K' isprecisely aligned with the feed nozzles of the nozzle block 2 andembodied such that it can firmly clamp the transverse wires Q, Q' and atthe same time, as will be explained below, sever them from the wirestock. The other feeder arm 9 is provided with a clamping device 12,which is capable of firmly clamping the transverse wires Q, Q'.

Once the transverse wires Q, Q' have been firmly clamped, the clampingdevices 11, 12 move along the paths of motion shown in FIG. 2 in thedirection of the arrows U, U', in order to sever the transverse wires Q,Q' from the wire stock and transfer them from the pickup positions K, K'to the welding lines S, S'. Once the welding of the transverse wires tothe longitudinal wires has been completed, the clamping devices 11, 12,with the aid of the feeder arms 8, 9, execute the motions shown in FIG.2 in the direction of the arrows 0, 0', in order to move out of thewelding lines S, S' into the pickup positions K, K' and pick up thetransverse wires Q, Q' that are ready in the feed lines K, K'.

The motions O, O' and U, U' are composed of two coupled individualmotions of the feeder arms 8, 9, specifically a substantially linearfeeding or pushing motion corresponding to the double arrow P₅ and arocking motion corresponding to the double arrow P₆.

The holder 10 is pivotably supported at one end of a rocking lever 13that is connected rigidly to a rocking shaft 14 at its other end. Thefeeding motion corresponding to the double arrow P₅ is executed by apushing device 15 comprising a cam plate and a rocking lever. Therocking lever 13 can be made to execute a rocking motion indicated bythe double arrow P₆ by means of a rocking device 16 comprising a camplate and a rocking lever.

In order to adhere to an exact transverse wire spacing, the transversewires Q, Q' are precisely positioned in the welding lines S, S' by meansof arms 17, 17' forming positioning devices, which project from a beam19 that is pivotable as indicated by the double arrow P₇ by means of aswivel drive mechanism 18 and which are provided on their free ends withdetent recesses for the transverse wires. During the pickup of thetransverse wires Q, Q' and during the welding process, the positioningarms 17, 17' assume an upper working position. The positioning arms 17,17' also have the task of damping the vibrations arising during thetransfer motion along the paths of motion U, U' in the transverse wiresQ, Q' and to eliminate them completely prior to the welding process. Thedetent recesses of the positioning arms 17, 17' have a mutual spacingthat advantageously matches the minimum possible basic spacing a of thetransverse wires. The positioning arms 17, 17' can be adjusted in theproduction direction P₁ by means of an adjuster 20, in order to beadapted precisely to the particular transverse wire spacing.

After the fixation by means of the clamping device 11, 12 explainedabove, the transverse wires Q, Q', during the feed motion along thepaths of motion U, U', are tightened with the aid of a clamping lever 22that is actuatable by a clamping cylinder 21 and pivotably supported inthe feeder arm 9 and that pivots the clamping device 12 outward in thetransverse wire direction or in the direction of the arrow P₈, in orderto eliminate any unevenness or wavyness in the transverse wires. Theprestressing of the transverse wires also avoids asymmetry in thefinished grid web resulting from thermal strains during welding. Thestressing force is adjusted in accordance with the particular strengthfigures for the transverse wires. If a hydraulic cylinder is used as thetightening cylinder 21, this is done for instance by suitable triggeringof the hydraulic pressure.

As FIG. 2 shows, the clamping device 11 comprises an upper clamping jaw23, 23' and a lower clamping jaw 24, 24'. The upper clamping jaw 23, 23'has a cutting edge on its side toward the nozzle block 2 that makes itpossible, in cooperation with a cutting edge on the trailing side of thenozzle block 2, to sever the transverse wires Q, Q' from the wire stockduring the feed motion of the arms 8, 9. The clamping device 12 of thefeeder arm 9 comprises an upper clamping jaw 25, 25' and a lowerclamping jaw 26, 26'. Each of the upper clamping jaws 23, 23' and 25,25' have a plurality of recesses, which are adapted in their dimensionsto the diameter of the transverse wire and which in their lateralspacing each correspond to the minimum possible basic spacing a of thetransverse wires.

The lower clamping jaws 24, 24'; 26, 26' have teeth or milled edgesextending transversely to the feed direction P₂, in order to increasethe frictional engagement between the clamping jaws and the transversewires Q, Q'.

Shunting in the welding of the two transverse wires Q, Q' to thelongitudinal wires L, the clamping jaws each comprise one part 23', 24',25', 26' that is toward the front in the feeding direction of thelongitudinal wire and a rear part 23, 24, 25, 26, each of which receiveonly one transverse wire and are insulated electrically from one anotherby an insulator 27 and are additionally insulated from the mounts of theclamping jaws in the feeder arms 8, 9.

After one welding operation has ended, the transverse wire feedingproceeds as follows: the clamping device 11 is opened, in that the lowerclamping jaw parts 24, 24' are first lowered in the direction of thearrow P₉ with the aid of a clamping lever 30 actuated by a clamp drivemechanism 28 and a clamping cylinder 29. At the same time, the clampingdevice 12 is opened by lowering the lower clamping jaw parts 26, 26' inthe direction of the arrow P₉ with the aid of a clamping lever 32actuated by a clamping cylinder 31. When the clamping jaws 25, 26 areopened, the clamping lever 22 completes its motion in the direction ofthe arrow P₈ and moves the clamping jaws 25, 26 into the terminalposition shown in dashed lines in FIG. 2. Next the clamping devices 11,12 are jointly transferred to the pickup positions K, K'. In thisprocess the upper clamping jaws move along the paths of motion O, O'shown in FIG. 2, while the lower clamping jaws are guided along paths ofmotion that are substantially parallel to the paths of motion O, O' butfor the sake of simplicity are not shown in FIG. 2.

Once the pickup positions K, K' have been reached, the clamping devices11, 12 are closed, in order to securely clamp the transverse wires Q,Q'. The closing motion in the direction of the arrow P₁₀ is effected bythe lower clamping jaws 24, 24' and 26, 26', is performed with the aidof the clamping lever 30, actuated by the clamp drive mechanism 28 andthe clamping cylinder 29, and with the aid of the clamping lever 32actuated by the clamping cylinder 31.

As shown in FIG. 3a, the welding current is supplied by transformers andbus bars, not shown, by means of a current feed 33 of a top electrode 34that is at the rear in the production direction P₁, and flows first viathe rear weld point, formed by the longitudinal wire L and the reartransverse wire Q, into a rear bottom electrode 35, and from there flowseither directly (FIG. 3b) or via electrically conducting electrodeseparators 36, 36' (FIG. 3a) into the front bottom electrode 35', andthen via the front welding point, formed by the longitudinal wire L andthe front transverse wire Q', into a front top electrode 34', and thenvia a current feed 33' is diverted to suitable bus bars.

The bottom electrodes 35, 35', and the electrode separators 36, 36' aremounted removably in a lower electrode mount 37. The two top electrodes34, 34' are electrically separated by an insulator 38. During thewelding process, the bottom electrodes 35, 35' are stationary, while thetop and electrodes 34, 34' are movable with the aid of an electrode beam39 as indicated by the double arrow P₁₁ and can thus be acted upon bythe necessary welding pressure. The top electrodes 34, 34' can beadapted individually in terms of their welding pressure to thedimensions of the longitudinal and transverse wires to be welded, bymeans of an adjusting screw 40 and an electrode spring 41.

In FIGS. 3a and 3b, possible welding positions A-G for the transversewires Q, Q' are schematically shown, each of which is equivalent to amultiple of a minimum possible basic spacing a. When grid webs havingthe minimum possible basic spacing a are produced, the welding positionsA-B are assumed. Then a somewhat modified front top electrode 34' havinga recess shown in dot-dash lines is used, in order to avoid re-weldingof the already welded transverse wire Q' located in position D. If atransverse wire spacing having twice the value of the basic spacing a isdesired, then either the welding positions A--D or C--B can be assumed.The welding position C--D is equivalent to three times the basic spacinga.

In the welding positions described above, the two bottom electrodes 35,35' are disposed adjacent one another, as shown in FIG. 3b. The weldingpositions E--D define four times the minimum possible basic spacing a.If five times the basic spacing a is desired, then the welding positionsF--D or E--G can be assumed. The welding position F--G allows atransverse wire spacing having six times the basic spacing a. As shownin FIG. 3a, in the lastnamed welding positions the bottom electrodes 35,35' are separated by the electrode separators 36, 36'.

To achieve exact orthogonality between the transverse wires Q, Q' andthe longitudinal wires L, the rocking shaft 14 can be adjustedunilaterally in the production direction P₁ by means of an eccentricadjustment 43 that can be positioned via an adjusting spindle 42. Thepositioning beam 19 can also be adjusted to exact orthogonality of thetransverse wires Q, Q' relative to the longitudinal wires L, with theaid of an adjusting eccentric 44.

When the transverse wire spacing is changed to a multiple of the minimumpossible basic spacing a, wires are supplied to the corresponding feednozzles of the nozzle block 2, and the plate holders 5, 5' and the flapshafts 6, 6' are adjusted (according) to the double arrow P₁₂. At thesame time, and as shown in FIGS. 3a and 3b, the bottom electrodes 35,35' and the electrode spacers 36, 36' can optionally change positionswith one another. If the minimum basic spacing a is to be fundamentallychanged, for instance from a one-inch basic spacing to a 20-mm basicspacing, then the nozzle block 2, clamping device 11, clamping device 12and positioning arms 17, 17' will all be replaced completely.

It is understood that the exemplary embodiment described can be modifiedin various ways within the scope of the concept of the invention.

I claim:
 1. A welding machine for manufacturing grids from longitudinaland transverse wires (Q, Q') intersecting one another at right anglesand welded together at the intersection points, havinga device fordelivering a plurality of longitudinal wires in a horizontal weldingplane; two feed devices, located on respective feed lines, mutuallyspaced-apart from each other, for simultaneous feeding of two transversewires; a welding electrode arrangement for performing double spotwelding in the direction of the longitudinal wires and defining aplurality of welding lines distributed over a range; two feeder arms (8,9) for transferring the transverse wires from the feed lines to thewelding lines; and a common feeder arm holder extending at right anglesto the longitudinal wire direction; the feeder arms being located onsaid common feeder arm holder, movable thereby, disposed outside theoutermost longitudinal wires and being movable back and forth onpredetermined paths of motion between the feed lines and the weldinglines, characterized in that the feeder arms (8, 9) are formed forreceiving both transverse wires (Q, Q') jointly; are equipped withclamping devices (11, 12) which are provided on said feeder arms for thetransverse wires (Q, Q'); at least one of the feeder arms (8, 9) ismovable relative to the other feeder arm in the transverse wiredirection for joint prestressing of both transverse wires (Q, Q'); amechanical drive mechanism (22) with adjustable stressing force isprovided, coupled to said at least one feeder arm; and positioningdevices (17, 17') are provided pivotable in the range of the weldinglines (S, S') for exact positioning of the transverse wires (Q, Q') inaccordance with a predetermined transverse wire spacing.
 2. The weldingmachine of claim 1, characterized in that for positioning, at least one(9) of the feeder arms is disposed displaceably on the feeder arm holder(10) relative to the other feeder arm (8).
 3. The welding machine ofclaim 1, characterized in that the positioning devices are formed byarms (17, 17') offstanding from a pivot shaft (19) extending across thewidth of the machine, the arms being provided in the region of theirfree ends with detent recesses for the transverse wires.
 4. The weldingmachine of claim 1, characterized in that the paths of motion (U, U') ofthe feeder arms (8, 9) for the transverse wires (Q, Q') comprises a pathfrom the feed lines (K, K') to the welding lines (S, S') and paths (O,O') from the feed lines and forming return motion paths;and wherein saidpaths each comprise one forward feed path segment (P₅) and one rockingmotion path segment (P₆).
 5. The welding machine of claim 1,characterized in that the clamping devices (11, 12) for the transversewires (Q, Q') have openable and closable lower clamping jaws (24, 24';26, 26'), which cooperate with associated upper clamping jaws (23, 23';25, 25'), and that the upper clamping jaws (23, 23'; 25, 25') are eachprovided with a plurality of detent recesses for receiving thetransverse wires, the mutual spacing of the recesses being equivalent tothe predetermined minimum transverse wire spacing (a).
 6. The weldingmachine of claim 5, characterized in that the upper clamping jaw (23,23') of that one (11) of the clamping devices (11, 12) located towardthe feed side forms a cutting tool, and that at least two transversewire feeds are provided in a nozzle block (2) toward the feed side, theoutlet side of which has a cutting edge for cooperation with the upperclamping jaw (23, 23') of the clamping device (11) on the feed sideforming the cutting tool, in order to sever the transverse wires (Q, Q')from the wire stock.
 7. The welding machine of claim 6, characterized inthat the lower clamping jaw (24, 24') of that one (11) of the clampingdevices (11, 12) located toward the feed side is actuatable by aclamping lever (30) that can be acted upon by means of a clampingcylinder (29) and a clamp drive mechanism (28), and that the lowerclamping jaw (26, 26') of the clamping device (12) remote from the feedside is actuatable relative to the associated upper clamping jaw (25,25') by a clamping lever (32) actuatable by means of a clamping cylinder(31).
 8. The welding machine of claim 5, characterized in that theclamping jaws (23, 23'; 24, 24'; 25, 25'; 26, 26') of the clampingdevices (11, 12) each comprise one part (23', 24'; 25', 26') to thefront in the longitudinal wire feeding direction (P₁) and one rear part(23, 24, 25, 26) which are separated from one another by an insulator(27).
 9. The welding machine of claim 6, characterized in that themutual spacings of the wire feeds in the nozzle block (2) and the mutualspacings of the detent recesses in the positioning devices (17, 17') andin the upper clamping jaws (23, 23'; 25, 25') are equivalent to theminimum possible basic spacing (a) of the transverse wires.
 10. Thewelding machine of claim 1, characterized in that the feeder arm (9)remote from the feed side is pivotable by the mechanical drive mechanism(22) in the transverse wire direction (Q, Q'), and the mechanical drivemechanism optionally has a clamping lever (22), which is actuatable by ahydraulic cylinder (21) that can be acted upon with adjustable pressure.11. The welding machine of claim 1, characterized in that the weldingelectrode arrangement includes a top and a bottom electrode means;andthe bottom electrode means (35, 35') can be repositioned for variouswelding positions (A-G) of the welding lines (S, S') (FIGS. 3a, 3b). 12.The welding machine of claim 1, characterized in that the weldingelectrode arrangement includes a top and a bottom electrode means;andthe top electrode means (34, 34') can be individually positioned bymeans of an adjusting screw (40) and an associated electrode spring(41).
 13. The welding machine of claim 1, characterized in that the feedlines (K, K') are each defined by at least one stationary plate (3, 3')and one pivotable flap (4, 4'), which between them define a transversewire guide (R).